Preclosure Pressure Gradients Predict Patent Ductus Arteriosus Patients at Risk for Later Left Pulmonary Artery Stenosis

The objective of this study was to evaluate the incidence of pre-existing catheterization left pulmonary artery (LPA) gradients and correlation of these gradients with later LPA stenosis after successful patent ductus arteriosus (PDA) occlusion. We performed a single-center review of 130 patients with PDA closure from October 1993 to February 2005. We analyzed the pre-PDA closure LPA pressure gradients at catheterization to determine if these were predictive of late LPA stenosis. On follow-up, a V _max >2 m/s by echocardiogram (transthoracic echocardiography; TTE) was considered indicative of possible LPA stenosis. Left lung perfusion of <35% was considered diagnostic of significant LPA stenosis. Post PDA closure, possible LPA stenosis by TTE was seen in 8 of 128 patients (6.25%). Seven of these eight had precatheter LPA gradients >7 mm Hg. Five of these had perfusion scans, three of the five had significant LPA stenosis, and two underwent LPA angioplasty. Patients with LPA catheter gradients >7 mm Hg were more likely to have possible LPA stenosis by TTE, significant LPA stenosis by lung scan, and intervention with LPA angioplasty. In conclusion, a preclosure main pulmonary artery-to-LPA pressure gradient >7 mm Hg was found in all patients who developed significant LPA stenosis on follow-up after transcatheter PDA closure. It appears likely that these patients have LPA abnormality rather than stenosis caused by the PDA occlusion device. Patients with preclosure LPA gradients >7 mm Hg should undergo follow-up evaluations for detection of significant stenosis and may require treatment if an important flow abnormality is documented.     

Can optical coherence tomography predict the outcome of laser photocoagulation for diabetic macular edema?

BACKGROUND AND OBJECTIVE: To assess the outcome of laser photocoagulation in patients with diabetic macular edema. PATIENTS AND METHODS: Forty-seven patients (51 eyes) with clinically significant macular edema (CSME) undergoing grid laser photocoagulation were included. Clinical examination and optical coherence tomography (OCT) were performed at baseline and 3 to 4 months after treatment. The central foveal thickness, mean inner macular thickness (average retinal thickness in fovea and inner macular circle), and mean macular thickness were calculated. Based on the greatest OCT thickness at baseline, patients were grouped according to mild (< 300 microm; Group 1), moderate (300 to 399 microm; Group 2), and severe (> or = 400 microm; Group 3) macular edema. RESULTS: Group 2 showed significant reductions in central foveal thickness (23 microm, P = .02), mean inner macular thickness (18 microm, P = .02), and mean macular thickness (9 microm, P = .04) with slight improvement in visual acuity. Groups 1 and 3 did not show any significant change in macular thickness values and there was a statistically insignificant worsening of visual acuity in these groups. CONCLUSIONS: Patients with moderate macular thickening of 300 to 400 microm benefit most from laser treatment. OCT may help in choosing the appropriate treatment for CSME based on the degree of macular thickening. Long-term studies are warranted to confirm these findings.     

Anticoagulant effect of Naja naja venom 5'nucleotidase: demonstration through the use of novel specific inhibitor, vanillic acid.

The snake venom proteins affect hemostasis by either advancing/delaying blood coagulation. Apart from proteases and phospholipase A(2)s (PLA(2)s), 5'nucleotidase is known to affect hemostasis by inhibiting platelet aggregation. In this study, the possible involvement of Naja naja venom 5'nucleotidase in mediating anticoagulant affect is evaluated. Vanillic acid selectively and specifically inhibited 5'nucleotidase activity among other enzymes present in N. naja venom. It is a competitive inhibitor as evident of inhibition relieving upon increased substrate concentration. Vanillic acid dose dependently inhibited the anticoagulant effect of N. naja venom up to 40%. This partial involvement of 5'nucleotidase in mediating anticoagulant effect is substantiated by concanavalin-A (Con-A) inhibition studies. Con-A, competitively inhibited in vitro protease and 5'nucleotidase activity up to 100%. However, it did not exhibit inhibitory activity on PLA(2). The complete inhibition of anticoagulant effect by Con-A upon recalcification time suggests the participation of both 5'nucleotidase and protease in mediating anticoagulant effect of N. naja venom. Vanillic acid and Con-A inhibition studies together suggest that probably 5'nucleotidase interacts with one or more factors of intrinsic pathway of blood coagulation to bring about anticoagulant effect. Thus, this study for the first time demonstrates the involvement of 5'nucleotidase in mediating N. naja venom anticoagulant effect.     

The p20 gene product of Citrus tristeza virus accumulates in the amorphous inclusion bodies

Citrus tristeza virus (CTV) has 10 3' open reading frames (ORFs) of unknown function except for the two coat proteins. The highest produced subgenomic RNAs are those of the major coat protein gene (p25) and the 3' most genes, p20 and p23. The proteins from three ORFs, p25, p27, and p20, were examined in the yeast two-hybrid assay for the interactions between themselves and to one another. The p20 protein exhibited a high affinity for itself, suggesting that it might aggregate in infected cells. The cytopathology of CTV infections includes characteristic paracrystalline and amorphous inclusions in the phloem elements of infected citrus. Polyclonal antiserum raised against the bacterial expressed p20 gene product detected a protein of approximately 22-23 kDa, which accumulated to relatively high levels in CTV-infected citrus, but not in healthy citrus. Immunogold localization using antibodies to p20 protein showed strong and specific labeling of the amorphous inclusion bodies present in CTV-infected cells. Mesophyll protoplasts of Nicotiana benthamiana transfected with a CTV mutant containing the green fluorescent protein (GFP) ORF fused in-frame to the 3' end of p20 protein ORF expressed high levels of GFP. The fusion protein was concentrated in one specific area in the cytoplasm and lacked an organized shape. Accumulation of high levels of p20 protein in infected tissue, specific localization of the p20-GFP fusion protein, immunolocalization of p20 protein into amorphous inclusions, and strong homologous p20 protein-p20 protein interactions in the yeast-two-hybrid assay suggest that the p20 protein of CTV is a major component of the amorphous inclusion bodies present in CTV-infected cells.     

Isolation of a protective gamma-globulin fraction interfering with the zinc sulphate turbidity test

The serum of a case of hyperglobulinaemia with negative thymol and zinc sulphate turbidity reactions was studied. The serum when added to pathological sera with high turbidity values brought about a marked reduction in the original turbidity values. Also, the serum did not give the usual copper proteinate precipitate when added to copper sulphate solutions. The anomalous protein fraction responsible for the above properties was isolated from the γ globulins by precipitation at 28% saturation with ammonium sulphate. It was found to be neither a macroglobulin (Waldenstrom's), a cryoglobulin, nor a collagen protein. Its occurrence in the very γ globulin fraction which is responsible for many of the turbidity reactions is of great significance in the interpretation of these tests. It is suggested that the normal turbidity and flocculation reactions reported in some cases of multiple myelomatosis might be due to some such anomalous proteins.     

Effects of an antimicrobial additive to toothbrushes on residual periodontal pathogens

OBJECTIVE: Previous studies have reported the link between residual microbial contamination of toothbrushes and periodontal diseases. The goal of this pilot study was to evaluate the effects of an antimicrobial additive (Microban) to toothbrushes on residual retention of periodontal pathogens. METHODOLOGY: Twenty patients had one side of their mouths brushed with a toothbrush containing the antimicrobial agent (experimental side), and the other side with a toothbrush containing no agent (control). Toothbrushes were air-dried (25 degrees C) for four or 24 hours. Toothbrush heads were vortexed and cultured for Prevotella species (Ps), Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), and non-specific colony-forming units (NS). The plates were incubated and counted. Means and standard deviations were calculated, and data were analyzed using a series of t-tests (paired and unpaired) and Wilcoxon matched-pairs signed-rank test. RESULTS: No significant inter- or intra-group differences in mean counts were found; however, when four-hour and 24-hour data for Aa, Pg, or NS were combined, experimental counts were lower than controls in 39/50 (78%) of the matched pairs (Wilcoxon signed-rank test p = 0.01). CONCLUSION: Toothbrushes containing the antimicrobial additive showed lower microbial counts than those without, but between-group means were not statistically significant.     

Ciprofloxacin- and hypocalcemia-induced torsade de pointes triggered by hemodialysis

Torsade de pointes is a polymorphic form of ventricular tachycardia associated with prolongation of the QT interval, which may be either congenital or acquired. Etiologies for the acquired forms include drug effects, hypokalemia, hypomagnesemia, hypocalcemia, starvation, sick sinus syndrome, and atrioventricular block. We present a 76-year-old man with acute on chronic renal failure, hypocalcemia, on ciprofloxacin, and a prolonged QT interval with torsade de pointes triggered by hemodialysis. The QT prolongation was corrected by treating the hypocalcemia. Hypocalcemia and ciprofloxacin are known to independently cause prolonged QT interval and torsade de pointes; our case illustrates that dialysis can trigger torsade on a background of this risk factor combination.